1. Field of the Invention
This invention relates to a catheter and obturator therefor which may be used for the application of a liquid along the length of a wound, and more particularly for the application of a local anesthetic agent along the length of the wound to cause analgesia of the wound.
2. Prior Art
After abdominal or other type surgery, analgesia is necessary for several days until operative wound pain has subsided. The most common analgesia used is a narcotic and/or a sedative which acts systemically, typically has undesirable side effects, such a respiratory depression, hypotension, nausea, paralytic ileus, clouding of sensorium and possible drug dependency. The drugs are usually given intramuscularly on a demand schedule, up to every three hours.
A preferred system of analgesia causes local blockage of the segmental nerves in the area of the operative wound using a long acting local anesthetic agent such as bupivacaine or etidacaine. These agents provide local analgesia for six hours or more when infiltrated into the area of the wound. Using known standard techniques, however, would require multiple needle injections of the local anesthic agent every six hours to provide continuous analgesia. Such a procedure is impractical and beyond the scope of customary nursing practice.
It is therefore highly desirable to provide analgesia of an operative wound without undesirable side effects of narcotics and sedatives by the use of a local anesthetic agent. It is further desirable to provide this local anesthetic agent to the operative wound continuously, or at the very least, intermittently, without the requirement for multiple needle injections. Additionally, such a procedure should be compatible with current surgical and nursing procedures.
Numerous catheter devices are known for various medical purposes, but none provides a device and/or method suitable for continuously or intermittently applying a local anesthetic agent to an operative wound to accomplish local blockade of multiple segemental nerves.
For example, U.S. Pat. No. 2,257,369 to Davis describes a combination catheter and drainage suitable for draining and medicating the bladder and the duct of the penis leading from the bladder cavity to the exterior through the penis. The catheter comprises an inner and outer tube, the outer tube having a plurality of ports or openings in the outer wall and communicating to the space between the inner and outer tube. The inner tube extends beyond the outer tube for a substantial distance to permit the inner tube to extend into the bladder cavity and permit drainage of the bladder cavity and irrigation.
U.S. Pat. No. 2,531,667 to Brent describes an apparatus for administering repeated injections. The apparatus comprises a syringe adapted to be strapped to the leg or arm of a patient, and which is provided with a flexible discharge tube adapted to dwell in a patient during the period of treatment. The flexible injection tube has an inlet end secured to the discharge end adapted to be inserted in a patient. The flexible injection tube or cannula is described as made of synthetic rubber, nylon or other flexible material and has a single discharge end inserted in a vein and remains in this position during treatment. The flexible tube is inserted into the vein by means of a trocar having a lumen slightly larger than the flexible tube. The trocar is first inserted in the vein and the flexible tube is slid through the trocar into its desired position in the vein and the trocar is then removed by sliding it backwardly over the flexible tube while holding the outer end of the tube to prevent its removal from the vein. This type device is unsuitable for the injection of local analgesia to an area of a patient.
U.S. Pat. No. 3,173,418 to Baran describes the use of a double-wall endotracheal cuff useful for continuous or intermittent local entracheal anesthesia through a perforated external cuff.
U.S. Pat. No. 3,312,220 to Eisenberg describes a plastic cannula which is designed to allow introduction into the patient over a steel needle. Following insertion of the plastic cannula the steel needle is withdrawn. The plastic cannula has a blunt tapered point at the leading end. The tapered end of the cannula is perforated with accessory drainage holes to forestall plugging should the tip of the cannula come in contact with the tissue surface or become plugged with proteinaceous material. The sharp steel needle permits the easy penetration of the cannula into the body wall.
U.S. Pat. No. 3,399,674 to Pannier et al describes a cannulated needle in telescopic association with the interior of a catheter. The needle projects out of the catheter on the distal end to facilitate venipuncture.
U.S. Pat. No. 3,459,188 to Roberts describes a catheter-stylet combination for puncturing a patients abdominal wall for peritoneal dialysis. A rigid wire stylet fits within a bore of a flexible plastic catheter and has a point on one end protruding from the catheter and a handle engaged on the opposite end of the catheter. The catheter has a larger internal bore than the stylets outer diameter and has a series of ports through the catheters wall extending from the one end to form a sieve portion permitting fluid to enter immediately after insertion. The stylet has an elongated piercing element which has a pointed end extending from the end of the catheter. When the stylet is withdrawn a large end port is provided in the catheter which precludes its use in the manner described herein.
U.S Pat. No. 3,598,119 to White and U.S. Pat. No. 3,508,545 to Reif et al describe catheter devices for placement within the body tissues with a retention means, to allow repeated injection of local anesthetic for paracervical anesthesia. These devices deliver the medication only at the catheter tip precluding their use to provide dispersion of a local anesthic agent along the length of an operative wound.
U.S. Pat. No. 3,670,729 to Bennett et al describes a transfusion needle having a sleeve which has a plurality of perforations which are spaced along its length to ensure the permanent flow of an anti-inflammatory fluid at the sight of entry of the transfusion needle. The device is used with a conventional steel needle having a sharp point inserted through the sleeve so that the point projects beyond the end of the sleeve. The needle with the device is then inserted into the patients vessel.
U.S. Pat. No. 3,680,562 to Wittes et al describes an apparatus for surgical catheter drainage which includes a flexible plastic tube inwardly curved at the distal end with tapered blunt tip and a longitudinally aligned outlet ports spaced on the inside of the curve at the distal end of the tube. within the tube is disposed a hollow piercing element having a bevelled point which extends beyond the distal end of the tube. The tapered blunt tip of the tube provides a close fit with the piercing element. The above assembly is inserted through the skin into the bladder and after being properly positioned, the piercing element is removed and the catheter tube is inserted into the bladder. As the piercing element is withdrawn from the catheter tubing, its distal end assumes a preformed coil or curve. This device does not permit the controlled dispersion of medicine along the length of the tube due to the open distal end.
U.S. Pat. No. 4,037,599 to Raulerson describes a continuous flow catheter device for intravascular placement during hemodialysis. This device does not permit even dispersion of a medication along a subcutaneous or muscular plane.
None of the foregoing catheter devices and assemblies are suitable for the continuous or intermittent application of a local anesthetic agent along the length of an operative wound over a long period of time. Additionally in all of the catheter devices the removable needle, trocar or stylet constitutes the piercing means necessitating the distal end of the catheter being open. Such an opening does not permit the even dispersion of the liquid passing therethrough.